Carefully designed and collected multi-method geophysical surveys can be used to measure the thickness of sediments above bedrock and to provide detailed fault mapping and stratigraphic information. It is also possible to differentiate fractured, weathered low RQD bedrock from competent bedrock and in some case differentiate certain rock types. Typical geophysical methods used are: Ground penetrating radar, DC-resistivity, electromagnetics and refraction/reflection seismic each providing different rock properties and depths of investigation.

In combination with strategically placed boreholes, geophysical methods offer a more continuous view of the subsurface than boreholes alone, with little or no environmental impact.
Electrical, electromagnetic, ground penetrating radar and refraction/reflection seismic methods are used in specific combinations to map rock properties at the required depths along HDD crossings.
Interpretive cross sections are provided showing the distribution of sand, gravel and boulder horizons, identifying aquifers and infilled collapse features as well as profiling the bedrock surface, within the limitations of geophysical investigation.